Westinghouse porcelain signals
   The Westinghouse High Voltage Insulator Company purchased the Pittsburg HVIC circa 1921. Pintype insulators would continue to be produced until 1953.
   
    Reported styles: U-247, U-249, U-277, U-280, U-281, U-283, U-284, U-286,
U-286A, U-288, U-291, U-292, U-293, U-297, U-298, U-299, U-300, U-306, U-308, U-309, U-310, U-314, U-316, U-334

    Reported colors: white, brown, gray, cobalt, chocolate brown, blue, light blue,           turquoise, green, cobalt, yellow, sky tone, caramel
Four U-281s  incised on dome "W" within circle and various production and model markings.
Eight U-284s incised on dome "W" within circle and various production and model markings.
U-288s under glaze markings on domes.
Similar to U-300. Both are ink stamped "W" in circle on dome
Nine U-314s. The first 2 seem to be incised "W" in circle on dome. The next six are ink stamped on dome.
These 4 are radio treated.